Methods of providing photolithography patterns using feature parameters, systems and computer program products implementing the same

ABSTRACT

A method of providing a photolithography pattern can be provided by identifying at least one weak feature from among a plurality of features included in a photolithography pattern based on a feature parameter that is compared to a predetermined identification threshold value for the feature parameter, A first region of the weak feature can be classified as a first dosage region and a second region of the weak feature can be classified as a second dosage region. Related methods and apparatus are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.13/950,708, filed Jul. 25, 2013 and claims priority from Korean PatentApplication No. 10-2012-0087353, filed on Aug. 9, 2012, in the KoreanIntellectual Property Office, the disclosure of which is incorporatedherein by reference in its entirety.

FIELD

The inventive concept relates to the field of photolithography, and moreparticularly, to photolithography for semiconductor fabrication.

BACKGROUND

In order to integrate as many devices as possible in a small area, thesize of individual devices should be reduced, and, for this purpose, thepitch between the patterns should be reduced. Due to the resolutionlimitations of the related photolithography processes, there may bedifficulties in forming patterns according to some design rules of thereduced pitch semiconductor devices.

SUMMARY

Embodiments according to the inventive concept can include methods ofproviding photolithography patterns using feature parameters, systemsand computer program products that implement such methods. Pursuant tothese embodiments, a method of providing a photolithography pattern canbe provided by identifying at least one weak feature from among aplurality of features included in a photolithography pattern based on afeature parameter that is compared to a predetermined identificationthreshold value for the feature parameter. A first region of the weakfeature can be classified as a first dosage region and a second regionof the weak feature can be classified as a second dosage region.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the inventive concept will be more clearlyunderstood from the following detailed description taken in conjunctionwith the accompanying drawings in which:

FIG. 1 is a flowchart showing a patterning method according to someembodiments of the present inventive concept;

FIG. 2 is a flowchart showing operation of detecting weak patterns ofFIG. 1, according to some embodiments of the present inventive concept;

FIG. 3 is a flowchart showing operations of detecting weak patternsaccording to some embodiments of the present inventive concept;

FIGS. 4A through 4C are comparative plan views illustrating effects ofthe patterning methods;

FIG. 5A is a drawing of a pattern illustrating a principle of thepatterning method according to some embodiments of the present inventiveconcept, and FIG. 5B is a drawing of a pattern formed using aconventional patterning method;

FIGS. 6A and 6B are plan views for explaining an application range ofthe patterning method according to some embodiments of the presentinventive concept;

FIG. 7 is a graph showing the number of assist features and mainfeatures formed on a mask;

FIGS. 8A through 8C are drawings illustrating weak pattern detectingmethods applied to a patterning method according to some embodiments ofthe present inventive concept;

FIG. 9 is a drawing illustrating weak pattern detecting methods appliedto a patterning method according to some embodiments of the presentinventive concept;

FIGS. 10A through 10E are drawings illustrating guidelines forclassifying shot regions with respect to detected weak patterns;

FIGS. 11A through 11E are drawings illustrating regions to whichoverlapping shots may be applied, according to some embodiments of thepresent inventive concept;

FIG. 12 is a flowchart illustrating forming a pattern on a targetsubstrate of FIG. 1 when the target substrate is a mask;

FIGS. 13A through 13D are cross-sectional views illustrating operationsof forming a pattern on a mask according to some embodiments of thepresent inventive concept;

FIG. 14 is a flowchart illustrating methods of fabricating asemiconductor device using the mask fabricated using the patterningmethod of FIG. 1;

FIG. 15 is a flowchart illustrating operations of forming patterns on atarget substrate of FIG. 1 when the target substrate is a semiconductorsubstrate; and

FIG. 16 is a block diagram illustrating a configuration of asemiconductor device manufacturing apparatus according to someembodiments of the present inventive concept.

DESCRIPTION OF THE EMBODIMENT ACCORDING TO THE INVENTIVE CONCEPT

The present inventive concept is described herein with reference to theaccompanying drawings, in which exemplary embodiments of the presentinvention are shown. This invention may, however, be embodied in manydifferent forms and should not construed as limited to the exemplaryembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the scope of the invention to those of ordinary skill in the art.

It will be understood that when an element or layer is referred to asbeing “connected to” another element or layer, the element or layer maybe directly connected to another element or layer or intervening a thirdelement or layer. Furthermore, when an element is referred to as being“on” another element or layer, the element or layer may be “directly on”or intervening a third element or layer. In the drawings, lengths andsizes of layers and regions may be exaggerated for clarity and elementsthat are not related to the description are removed. Also, likereference numerals refer to like elements throughout. The terminologyused herein is for the purpose of describing particular embodiments onlyand is not intended to be limiting of the invention.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, these elements should notbe limited by these terms. These terms are only used to distinguish oneelement from another. For example, a first element could be termed asecond element, and, similarly, a second element could be termed a firstelement, without departing from the scope of the disclosure. As usedherein, the term “and/or” includes any and all combinations of one ormore of the associated listed items.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the inventiveconcepts. As used herein, the singular forms “a”, “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises,” “comprising,” “includes” and/or “including” when usedherein, specify the presence of stated features, integers, steps,operations, elements, and/or components, but do not preclude thepresence or addition of one or more other features, integers, steps,operations, elements, components, and/or groups thereof.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure belongs. It willbe further understood that terms used herein should be interpreted ashaving a meaning that is consistent with their meaning in the context ofthis specification and the relevant art and will not be interpreted inan idealized or overly formal sense unless expressly so defined herein.

Many different embodiments are disclosed herein, in connection with theabove description and the drawings. It will be understood that it wouldbe unduly repetitious and obfuscating to literally describe andillustrate every combination and subcombination of these embodiments.Accordingly, all embodiments can be combined in any way and/orcombination, and the present specification, including the drawings,shall be construed to constitute a complete written description of allcombinations and subcombinations of the embodiments described herein,and of the manner and process of making and using them, and shallsupport claims to any such combination or subcombination.

FIG. 1 is a flowchart showing a patterning method according to someembodiments of the present invention.

Referring to FIG. 1, of patterns to be formed on a target substrate,weak patterns may have a high possibility of failure are detected(S110). The target substrate may be a mask used in photolithographyprocess or may be a semiconductor substrate on which semiconductordevices are formed.

The semiconductor substrate may be a semiconductor wafer, for example,may include a group IV material or a group III-V compound. Thesemiconductor substrate may be formed to be a mono-crystal wafer such asa silicon mono-crystal. The semiconductor substrate is not limited to amono-crystal wafer, as various wafers, such as an epi or epitaxialwafer, a polished wafer, an annealed wafer, a silicon-on-insulator(SOI), may be used. Here, the epitaxial wafer refers to a wafer obtainedby growing a crystalline material on a mono-crystal silicon substrate.

A photomask is an element used to form patterns on a semiconductorsubstrate through a photolithography process in a semiconductor devicemanufacturing process. Generally, a base plate is formed of quartzmaterial having a thin chrome film thereon (referred to as a blank mask)The mask can be completed when the blank mask is patterned using a laseror an e-beam. In the case of e-beam lithography process, there may bedifficulties in providing minute patterning because a high sensitiveresist may be used.

The blank mask may be classified as two kinds, that is, a binary mask(BIM) and a phase shift mask (PSM) according to the presence of atransparent film that may be referred to as a “phase conversion film”.The phase conversion film included in the PSM can reduce light from anexposure apparatus. As a further minute pattern may be used in a highlyintegrated semiconductor apparatus, the PSM that reduces intensity oflight may be used for forming a high resolution minute circuit pattern.

As appreciated by the present inventors, patterns that have featureswith a pattern relatively probability of failure may be detected byusing various methods, for example, by modeling or a predetermined rule.The weak features can be detected by using an inclination of the patternseparated via a convolution integral of a designed pattern and a modeledpattern. In some embodiments, weak features can be detected by usingpredetermined rules according to a distance between vertexes adjacent toeach other in the features or according to the number of vertexesincluded in a unit area. An identification threshold can be used todistinguish which patterns are weak and those that are not consideredweak.

After detecting weak features, the detected weak features can beclassified as at least two shot regions (S130). The classifying of theweak features as at least two shot regions may be performed by variousmethods. In some embodiments, classifying the weak features as at leasttwo shot regions can be provided by classifying based on the distancebetween vertexes in the weak features. For example, a quadrangle ortriangle shape (ie., portion of the pattern) adjacent to each ofvertexes, or a quadrangle shape extending along a side that connects twovertexes may be classified as a second shot region, and a remainingregion may be classified as a first shot region. In some embodiments,all of the weak features may be classified as the second shot region.Here, the first shot region may be understood as a region on which anexposure is performed by a single shot, and the second shot region maybe understood as a region on which an exposure is performed by specificshots, such as an overlap shot that at least partially overlaps thefirst shot region. The classifications and type of the shot regions willbe described in detail with reference to FIG. 10A through 11E using aclassification threshold in some embodiments.

After classifying the shot regions, patterns are formed on a targetsubstrate by performing exposures by applying different shot to theclassified shot regions (S150). In some embodiments, shots may be, asdescribed above, overlapping shots or shots where dosage may be variedamount.

In the patterning method according to an embodiment of the presentinvention, weak features of patterns to be designed are detected and areclassified as at least two shot regions. Then, the shot regions areexposed by applying different shot methods, for example, by performingoverlapping shots or by controlling the dosage of the shot. Therefore,the failure of patterns may be reduced while maintaining processstability. For example, overlapping shots may address line edgeroughness (LER), line end shortening, and minimum resolution, etc.,which may increase process stability.

FIG. 2 is a flowchart showing the operation of detecting weak features(S110) of FIG. 1, according to some embodiments of the present inventiveconcept.

Referring to FIG. 2, a pattern of a mask to be formed is designed(S112). That is, a pattern to be formed on the mask is designed based onthe pattern to be formed on a semiconductor substrate. In someembodiments, the pattern is formed using a computer software package.

Next, a modeling with respect to the mask pattern is performed (S114).It will be understood that the modeling can be provided by calculating adifference in the shape of the mask pattern compared to the shape thatis transferred onto a wafer using the mask pattern using simulation. Thesimulation can be performed using models set with respect to variousshapes features found in the mask which can be prepared in advance,whereupon the mask pattern can be compensated or modeled based on thecalculation result.

A convolution integral of a designed pattern and a modeled pattern isperformed (S116). The convolution integral is a mathematical conceptthat is generally known to those of ordinary skill in the art, and thus,the description thereof is omitted. An inclination is measured withrespect to a shape obtained as a result of the convolution integral andregions that have low inclination may be detected as weak features(S118). Low inclination can indicate that many deformations may occur atthe corresponding feature, and since there is a high probability thatthe deformation may cause a pattern failure, the regions that have anassociated low inclination, can be detected as weak features.

FIG. 3 is a flowchart showing operations of detecting weak features withrespect to the operation of detecting weak features (S110), according tosome embodiments of the present inventive concept.

Referring to FIG. 3, first, a mask pattern to be formed is designed(S112). Next, an inspection of the features in the designed pattern isperformed (S113). For example, the inspection includes inspection ofshapes of the features and vertexes included in each of the features,and also, inspection of distances between adjacent vertexes. The shapesand the distances between the vertexes may be extracted from data of thedesigned pattern.

Weak features are detected by applying predetermined rules with respectto the inspected pattern (S115). Features that include vertexescorresponding to the case, for example, when a distance between adjacentvertexes is less than an identification threshold may be identified asweak features. As another example when the number of vertexes per unitarea is equal to or greater than the identification threshold, thecorresponding features may be identified as weak features.

Although methods of identifying weak features in relation to a maskpattern are described with reference to FIGS. 2 and 3. Weak features mayalso be identified when features are formed on a semiconductor substrateby using a laser or an e-beam.

FIGS. 4A through 4C are plan views for explaining an effect of thepatterning method according to some embodiments of the presentinvention. FIG. 4A is a plan view showing a designed pattern to beformed on a mask, FIG. 4B is a plan view showing a pattern actuallyformed on a mask by using overlapping shots, and FIG. 4C is a plan viewshowing a pattern actually formed on a mask without overlapping shot, asa comparative example.

Referring to FIG. 4A, as described above, FIG. 4A shows a designedpattern with respect to a pattern to be formed on a mask. The patternhaving a relatively wide width may include main features 102, andpatterns having a relatively narrow width may be assist features 104.The assist features 104 may include a scattering bar SB and/or ananti-scattering bar ASB.

Referring to FIG. 4B, it is seen that patterns practically formed byoverlapping shots may be similar to the designed pattern of FIG. 4A.That is, the pattern formed on the mask may be similar to the designedpattern except that vertically contacting edge portions may be slightlycurved and both edges of long axes of the assist features 104 may berounded.

Referring to FIG. 4C, as indicated by an arrow, when overlapping shotsare not applied, the assist features 104 may be shortened, which cancause pattern failure. Pattern failure may be caused because anincorrect shot is performed due to the small size of the assist features104 or an insufficient dosage is irradiated onto the correspondingregions.

Accordingly, in the patterning method according to the currentembodiments, shot regions can distinguished with respect to weakfeatures to which pattern failure may occur, and overlapping shots maybe performed on those regions where pattern failures may occur. Insteadof overlapping shots, a method of controlling dosage according to theshot regions may be applied. For example, a shot with a high dose isperformed on regions where pattern failures occur, and a shot with aregular or reduced dose may be performed on remaining regions.

FIG. 5A is a drawing illustrating a patterning method according to someembodiments of the present invention, and FIG. 5B is a drawingillustrating a conventional patterning as a comparative example.

Referring to FIG. 5A, the upper feature is a designed feature 105 to beformed on a mask, and the lower pattern is a practical feature 107actually formed on the mask. The designed feature 105 may be classifiedas two regions (or portions), that is, a first shot region 105 a ontowhich a single shot is performed and a second shot region 105 b ontowhich at least two shots are performed.

The dosage irradiated onto the second shot region 105 b may be increasedsince at least two shots are performed in the second shot region 105 b.It will be understood that the dosage may be controlled by overlappingshots or by varying the dosage in a single shot. Accordingly, as it isdepicted in FIG. 5A, that the practical feature 107 having the sameshape as the designed pattern 105 may be formed. It will be understoodthat, a rounding phenomenon at the edge may still remain as shown. Inregard to the rounding phenomenon, a method of adding a serifcompensation feature on the edge portion of the pattern or a method ofperforming shots more than three times on the two vertexes may beconsidered.

Referring to FIG. 5B, the upper feature is a designed feature 105′ to beformed on a mask, and the lower feature is practical feature 107′actually formed on the mask. In the case when the designed feature 105′is exposed by a single shot without distinguishing regions, as depictedin FIG. 5B, a pattern failure of reducing edge may occur. For example,the practical feature 107′ has a length shorter by as much as a firstwidth w1 than the length of the designed feature 105′. In this way, thereduced length of the practical feature 107′ may cause a mask patternfailure and/or a pattern failure of a semiconductor substrate.

FIGS. 6A and 6B are plan views for explaining an application range ofthe patterning method according to some embodiments of the presentinvention.

Referring to FIG. 6A, features to be formed on a mask or a semiconductorsubstrate may be largely classified as main features 102 and assistfeatures 104. Generally, the pattern failure can occur in the assistfeatures 104 due to the smaller size. As depicted in FIG. 6A, in thecase of a simple pattern, overlapping shots or a controlled dosage maybe applied to the assist features. Accordingly, a patterning process maybe relatively readily performed.

Referring to FIG. 6B, features to be formed on a mask or a semiconductorsubstrate may not be clearly designated as main or assist features andmay have complicated shapes. In the case of a complicated pattern, manypattern failures can occur. As appreciated by the present inventors, itmay be difficult to predict which feature may cause a pattern failure. Amethod to correctly detect weak features regardless of the complexity ofthe pattern may be advantageous.

In some embodiments, the methods described with reference to FIGS. 2 and3 may be used to identify weak features. When a feature is notcomplicated but should be high quality, a pattern failure may occur inmain features. In this case, even in a simple pattern, it weakness of amain features may need to be identified.

FIG. 7 is a graph showing the number of assist features and mainfeatures formed on a mask and the possibility of generating qualityfailure. Here, a x axis indicates the size of features, and an y axisindicates the number of features corresponding to the sizes in a mask.The higher hatching concentration indicates higher possibility ofgenerating a pattern failure.

Referring to FIG. 7, as it is seen from the graph, many features havinga relatively large size are formed in the mask, and fewer featureshaving a small size, for example, ASB or SB are formed. Also, asindicated by arrows, relatively large size features are main features,and relatively small size features are assist features.

When the hatching concentration is considered, it is seen that manypattern failures can occur in small size features, for example, assistfeatures. However, it is seen that the pattern failures may also occurin the relatively small main features, and also, in the case of thelarge size main features, such that large size main features may alsohave a pattern failure.

In this way, since the occurrence of pattern failures may not be limitedto the small size features, but in all range of sizes, there may be alimit in identifying weak features only based on the size of patterns.In particular, in the case of a complicated pattern as depicted in FIG.6B, the possibility of generating the pattern failure may be high in themain features and irregular patterns.

FIGS. 8A through 8C are conceptual drawings for explaining another weakpattern detecting method that is applied to a patterning methodaccording to an embodiment of the present invention.

Referring to FIGS. 8A through 8C, FIG. 8A shows a pattern includingfeatures to be formed. A feature can be identified as being weak, when adistance between adjacent vertexes in the feature is less than areference distance. Reference numeral 102 indicates a main feature andreference numeral 104 indicates an assist feature.

More specifically, when vertexes (such as a corner) are extracted from afeature that is located second from the left side of the figure, thevertexes may have a structure as depicted in FIG. 8B. In this vertexstructure, when a distance to an adjacent vertex from one of thevertexes as a basis, for example, the vertex in a portion A hatched by acircle, that is, a distance a to a vertex in a horizontal direction anda distance b to a vertex in a vertical direction are less than referencedistances, the corresponding feature may be identified as a weakfeature. The reference distances may be in a range from about 10 nm toabout 60 nm. For example, when a high patterning quality is desired, thereference may be set to about 10 nm, whereas when regular patterningquality is desired, the reference may be set to about 60 nm.

FIG. 8C shows regions to which an overlap shot can be applied or a largeamount of dose can be applied after identifying a weak feature. That is,the black portion can be designated as a first shot region 102 a ontowhich a single shot is performed or a shot with a regular dosage isperformed, and the portions hatched by dots may be second shot regions102 b onto which at least two shots (such as the first shot and a secondshot) are performed or a shot with a large dosage is performed. In thecase of the assist features 104, the assist features 104 may correspondto mostly weak patterns since widths of the patterns may be very small,and are classified as the second shot region 104 b to which an overlapshot is performed or a shot with a large dosage is performed withrespect to entire assist features 104 according to a predetermined rule.

After identifying weak features, rules for classifying a predeterminedportion of a weak pattern as an overlap shot region are described infurther detail with reference to FIGS. 10A through 11E.

FIG. 9 is a drawing explaining some methods of identifying weak featuresapplied to the patterning method according to some embodiments of thepresent invention.

Referring to FIG. 9, in the patterning method according to the currentembodiment, weak features can be determined according to whether thenumber of vertexes per unit area is greater than a predetermined numberor not. For example, when there is a pattern as depicted in FIG. 9, thenumber of vertexes included in a unit area as indicated by the dottedline is calculated. Afterwards, whether the feature is weak or not isdetermined based on whether the calculated number of the vertexes isgreater than a reference number (i.e., a threshold) or not.

It will be understood that, in the present embodiment, the unit areaover which the number for vertexes is determined can be treated as afeature so that the identification of the feature as weak lead to asubsequent classification of that feature. Accordingly, it will beunderstood that term “feature” can include both an individual feature aswell as a group of individual features that are treated, as one feature.

In some embodiments according to the inventive concept, the number ofvertexes of the rightmost main feature may not be included in thedetermination of a weak feature. Also, most of the assist features 104may be weak features because the size of the assist features 104 issmall, and thus, vertexes of the assist features 104 may be not includedin the determination of a weak feature. Additionally, the unit area mayhave an arbitrary shape or size according to the user, and the referencenumber of vertexes may also be arbitrarily determined. For example, theunit area may be 5×5 μm², and the reference number may be greater than1000 vertexes.

In the case when the weak features are detected by the number ofvertexes per unit area, the rule to classify the weak features as shotregions may be the same as the rule for classifying shot regions withrespect to the weak patterns detected according to the distance betweenadjacent vertexes. In some embodiments according to the inventiveconcept, other shot region classifying methods may be applied.

FIGS. 10A through 10E are drawings illustrating rules for classifyingshot regions with respect to identifying weak features.

FIG. 10A shows a portion of a feature identified as a weak in whichvertexes and lines that connect the vertexes are shown. Here, when thevertex in a portion A hatched in a circle is a reference vertex, a firstdistance between the vertexes adjacent in a horizontal direction may be(a) and a second distance between the vertexes adjacent in a verticaldirection may be (b).

It will be understood that a classification threshold can be used todetermine how identified weak features are to be processed. For example,in some embodiments, when the threshold is a first value, the weakfeature can be classified a particular way based on a comparison of thedistance to the first vertex. When, however, the threshold is a secondvalue, a different classification can be used for the same distance tothe first vertex.

Referring to FIG. 10B, when the first distance a is greater than a firstreference distance d1 (sometimes referred to herein as a classificationthreshold value), the problem of reducing an edge portion does notoccur. In this case, an overlap shot may be performed onto the vertexes.Accordingly, when the first distance a is greater than a first referencedistance d1, portions of the pattern close to the vertexes may beclassified as a region to which an overlap shot or a shot with a largedosage is provided, that is, a second shot region S2, and remainingportions of the pattern may be classified as a region to which a singleshot is performed, that is, a first shot region S1. The second shotregion S2 may have a rectangular shape. Also, the second shot region S2may be defined as a shape different from the rectangular shape. Forreference, the phenomenon of rounding of the edge portion of the patternmay be mitigated to some degree by applying a overlap shot onto thevertexes. The first reference distance d1 may be arbitrary determined bythe user. For example, the first reference distance d1 may be 200 nm.

Referring to FIG. 10C, since the problem of reducing an edge portionoccurs when the first distance a is smaller than the first referencedistance d1, a single overlap shot may be performed on one big regioninstead of respectively performing overlap shots on two vertexes.Accordingly, when the first distance a is smaller than the firstreference distance d1 and is greater than the second reference distanced2, the second shot region S2 may have an extended rectangular shapethat connects two vertexes. Also, the second shot region S2 may bedefined as a shape different from the rectangular shape. The secondreference distance d2 may also be arbitrary determined by the user, forexample, may be 80 nm.

Referring to FIG. 10D, when the first distance a is smaller than thesecond reference distance d2 and is greater than a third referencedistance d3, the second shot region S2 may include an extendedrectangular shape that connects the two lower vertexes and an extendedrectangular shape that connects one of vertexes on either sides, forexample, from the vertex of a lower right side to the vertex in avertical direction.

When a distance between two vertexes is short, a pattern failure, thatis, a line edge roughness (LER) may occur on sides adjacent to eachother. Therefore, the pattern failure may be minimized by performing anoverlap shot or a shot with a large amount of dose on the sides. Also,the second shot region S2 may be defined as a shape different from theshapes depicted in the drawings. The third reference distance d3 mayalso be arbitrary determined by the user, for example, may be 60 nm.

Referring to FIG. 10E, when the first distance a is smaller than thethird reference distance d3 and is greater than a fourth referencedistance d4, the entire pattern may be classified as a second shotregion S2. Accordingly, an overlap shot or a shot with a large amount ofdose may be performed with respect to the entire pattern. The fourthreference may also be arbitrary determined by the user, for example, maybe 50 nm.

Up to now, numeral values about the first through fourth referencedistances are described. However, the d numeral values are exemplary,and thus, may be modified by the user. Also, up to now, the descriptionis made with referring to the first distance a. However, a similar rulemay be applied to the second distance b, and also, the division of shotregions may be performed in consideration of both the first and seconddistances a and b together.

As described above, any number of classification threshold values (i.e.,one or more than one) may be established to determine how a particularweak feature should be classified, and therefore subjected to varyingshapes, dosages, and numbers of single and/or overlapping shots based onthe distance measured between the vertexes compared to theclassification threshold(s).

FIGS. 11A through 11E are drawings illustrating regions to which anothertype of overlapping shots are applied, according to some embodiments ofthe present invention.

Referring to FIG. 11A, as depicted in FIG. 11A, the identified weakfeature 105 may be classified as including a first shot region S1 whichis a center region of the weak feature 105 and a second shot region S2that surrounds the first shot region S1.

Referring to FIG. 11B, the identified weak feature 105, similar to theweak feature of FIG. 11A, may be classified as including a first shotregion S1, which is a center region of the weak feature 105 and a secondshot region S2 that surrounds the first shot region S1. However, thesecond shot region S2 may be classified as second-1 shot regions S2′ andsecond-2 shot regions S2″. For example, the second-1 shot regions S2′may be regions to which two times of shots are performed and thesecond-2 shot regions S2″ may be regions to which three shots areperformed. Accordingly, a large dosage can be provided to the vertexesat the edges of the future in consideration of a further numbers ofpattern failures occurring on the vertexes at the edges of the feature.In the current embodiment, the numbers of shots are exemplary.Accordingly, the user may allocate various numbers of shots according tothe classified shot regions.

Referring to FIG. 11C, the identified weak feature 105 is classified toinclude a first shot region S1 and second shot regions S2. However, thesecond shot regions S2 are not allocated on a right edge of the firstshot region S1 but may have a rectangular shape extending along bothsides of the first shot region S1. If the second shot regions S2 areallocated as described above, this case may correspond to a case that alarge LER occurs on the sides of a formed pattern when the pattern isformed through a single shot.

Referring to FIG. 11D, in the identified weak feature 105, like in thepattern of FIG. 10B, second shot regions S2 are allocated close tocorresponding vertexes. However, the shape of the second shot regions S2is a triangle shape not a rectangular shape. However, the shape of thesecond shot regions S2 is not limited to a triangle shape or arectangular shape adjacent to the corresponding vertexes. For example,the second shot regions S2 may be defined as a various shapes, such as acircle, an oval, or another angle shape.

Referring to FIG. 11E, in the identified weak feature 105, like in thepattern of FIG. 10C, the second shot region S2 is allocated on an edgeportion of the pattern. However, unlike in the pattern of FIG. 10C, thesecond shot region S2 may have a curved shape that surrounds an edge ofthe first shot region S1. In other words, the edge portion of the firstshot region S1 that contacts the second shot region S2 may have a curvedshape.

Up to now, various types of the first shot region S1 and the second shotregions S2 are described. However, the shot regions according to thepresent embodiments are not limited thereto, that is, the second shotregions S2 may be allocated to any shape to reduce the occurrence ofpattern failures.

FIG. 12 is a flowchart further showing the formation of a pattern on atarget substrate (S150) of FIG. 1 when the target substrate is a mask.

Referring to FIG. 12, first, a first feature is formed in a resist on amask by applying shot methods different according to the shot regions(S152). As described above, the shot methods different according to theshot regions denotes performing an overlap shot or shots with differentdosages. The resist may be, for example, for performing a laser or ane-beam lithography. In the current embodiment, the resist may be ane-beam resist for performing an e-beam lithography.

With respect to the resist, exposing is performed by applying shotmethods different according to the shot regions, and a developingprocess is performed, and thus, the first feature is formed.

Next, a pattern is formed in the mask by etching the mask using thefirst pattern as an etch-mask (S154). The formed mask may be used as aphotomask in a photolithography process with respect to a semiconductorsubstrate.

FIGS. 13A through 13D are cross-sectional views showing formation offeatures of a pattern on a mask according to an embodiment of thepresent invention.

Referring to FIG. 13A, a blank mask in which a metal thin film 220 and aresist film 230 are sequentially formed on a mask substrate 210 isprepared. The mask substrate 210 may be an ordinary quartz substrate.Also, the metal thin film 220 may be, for example, a chrome thin film,and the resist film 230 may be an e-beam resist film for performing ane-beam lithography.

Referring to FIG. 13B, exposing is performed by applying shot methodsdifferent according to shot regions. Here, as described above, the shotmethods different according to shot regions may denote an overlap shotor shots with different dosages. After exposing, the resist film 230 maybe classified as three regions, for example, a first region 232 ontowhich an e-beam is not irradiated, region onto which an e-beam isirradiated, that is, a second region 234 onto which a single time ofe-beam is irradiated, and a region onto which at least two times ofe-beam are irradiated, that is, a third region 236 onto which an overlapshot is performed.

Referring to FIG. 13C, a resist pattern 230 b is formed by performing adeveloping process. In the current embodiment, the regions onto whichthe e-beam is irradiated remain as the resist pattern 230 b. However, insome cases, vice versa. For example, when a laser is used to expose,regions onto which the laser is not irradiated may remain as a patternaccording to the material of the resist.

Referring to FIG. 13D, a metal pattern 220 a is formed by etching themetal thin film 220 by using the resist pattern 230 b as an etch-mask.The forming of a mask, for example, a photomask may be completed byforming the metal pattern 220 a on the mask substrate 210.

FIG. 14 is a flowchart showing methods of forming a semiconductor deviceusing the mask fabricated according to FIG. 1.

Referring to FIG. 14, first, as in the patterning method described withreference to FIG. 1, weak features are identified (S110), and the weakfeatures are classified as at least two shot regions (S130). A maskpattern, including the features, is formed in a mask by applying shotmethods different according to the classified shot regions (S150). Here,the mask may be a photomask that is used for a photolithography process.

After forming the photomask, a device is formed on a semiconductorsubstrate by using the photomask. More specifically, a first feature isformed in a photoresist on the semiconductor substrate by performing aphotolithography process that includes an exposing process by using thephotomask and a developing process. Afterwards, a device can be formedby etching a target material layer on the semiconductor substrate byusing the first feature as an etch-mask.

Various semiconductor devices may be formed on the semiconductorsubstrate by repeatedly performing various processes, such as aphotolithography process using a photomask, an etching process, adeposition process with respect to material layers or photoresist, and aCMP process or washing process. Also, after forming the semiconductordevices on a semiconductor substrate such as a wafer, the semiconductordevices may be singulated into individual semiconductor devices, andthen, the individual semiconductor devices may be packaged, or afterpackaging on a wafer level, the individual semiconductor devices aresingulated into individual packages. In this way, semiconductor devicesor semiconductor packages may be fabricated.

FIG. 15 is a flowchart illustrating formation of a pattern, includingfeatures, on a target substrate when the target substrate of FIG. 1 is asemiconductor substrate (S150).

Referring to FIG. 15, as in the patterning method described withreference to FIG. 1, weak features are identified (S110), and the weakfeatures are classified as at least two shot regions (S130). A firstfeature is formed in a resist on a semiconductor substrate by applyingshot methods different according to the classified shot regions (S162).The forming of the first feature in the resist on the semiconductorsubstrate is similar to the forming of the first feature in the resiston the mask in FIG. 12. However, while an exposure may be performed byusing a laser or an e-beam with respect to the resist on the mask, anexposure may be performed by using a laser that is generally used for aphotolithography process with respect to the resist on the semiconductorsubstrate. However, the exposure by using an e-beam is not excluded.

Next, a device can be formed on a semiconductor substrate by using thepattern with the first feature as an etch-mask (S164). The devicefeature may be formed on a semiconductor substrate or may be formed on atarget material layer stacked on a semiconductor substrate.

In the current embodiment, unlike in FIG. 1, a pattern may be directlyformed on a semiconductor substrate without using a mask. In this way, amethod of forming a pattern directly on a semiconductor substratewithout using a mask is referred to as a direct patterning.

Various patterning methods, for example, the methods of patterningdescribed with reference to FIGS. 1 through 3 and 12, and the methods offabricating a semiconductor device described with reference to, forexample, FIGS. 14 and 15 have been described as operations carried outby a semiconductor integration circuit design program, that may be ableto be performed by a computer. In this way, some portions or all of thepatterning method and the method of fabricating a semiconductor device,according to the current embodiment may be realized by performing thesemiconductor integration circuit design program with a computer.Accordingly, the patterning method and the method of fabricating asemiconductor device according to the current embodiment may be realizedto a computer readable code in a computer readable recording medium.

Accordingly, aspects of the present disclosure may be implementedentirely hardware, entirely software (including firmware, residentsoftware, micro-code, etc.) or combining software and hardwareimplementation that may all generally be referred to herein as a“circuit,” “controller,”, “module,” “component,” or “system.”Furthermore, aspects of the present disclosure may take the form of acomputer program product comprising one or more computer readable mediahaving computer readable program code embodied thereon.

Any combination of one or more computer readable media may be used. Thecomputer readable media may be a computer readable signal medium or acomputer readable storage medium. A computer readable storage medium maybe, for example, but not limited to, an electronic, magnetic, optical,electromagnetic, or semiconductor system, apparatus, or device, or anysuitable combination of the foregoing. More specific examples (anon-exhaustive list) of the computer readable storage medium wouldinclude the following: a portable computer diskette, a hard disk, arandom access memory (RAM), a read-only memory (ROM), an erasableprogrammable read-only memory (EPROM or Flash memory), an appropriateoptical fiber with a repeater, a portable compact disc read-only memory(CD-ROM), an optical storage device, a magnetic storage device, or anysuitable combination of the foregoing. In the context of this document,a computer readable storage medium may be any tangible medium that cancontain, or store a program for use by or in connection with aninstruction execution system, apparatus, or device.

A computer readable signal medium may include a propagated data signalwith computer readable program code embodied therein, for example, inbaseband or as part of a carrier wave. Such a propagated signal may takeany of a variety of forms, including, but not limited to,electro-magnetic, optical, or any suitable combination thereof. Acomputer readable signal medium may be any computer readable medium thatis not a computer readable storage medium and that can communicate,propagate, or transport a program for use by or in connection with aninstruction execution system, apparatus, or device. Program codeembodied on a computer readable signal medium may be transmitted usingany appropriate medium, including but not limited to wireless, wireline,optical fiber cable, RF, etc., or any suitable combination of theforegoing.

Computer program code for carrying out operations for aspects of thepresent disclosure may be written in any combination of one or moreprogramming languages, including an object oriented programming languagesuch as Java, Scala, Smalltalk, Eiffel, JADE, Emerald, C++, C#, VB.NET,Python or the like, conventional procedural programming languages, suchas the “C” programming language, Visual Basic, Fortran 2003, Perl, COBOL2002, PHP, ABAP, assembly language, dynamic programming languages suchas Python, Ruby and Groovy, or other programming languages.

Aspects of the present disclosure are described herein with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems), and computer program products according to embodiments of thedisclosure. It will be understood that each block of the diagrams, andcombinations of diagrams, can be implemented by computer programinstructions. These computer program instructions may be provided to acontroller (or processor) of a general purpose computer, special purposecomputer, or other programmable data processing apparatus to produce amachine, such that the instructions, which execute via the processor ofthe computer or other programmable instruction execution apparatus,create a mechanism for implementing the functions/acts specified in thediagram.

These computer program instructions may also be stored in a computerreadable medium that when executed can direct a computer, otherprogrammable data processing apparatus, or other devices to function ina particular manner, such that the instructions when stored in thecomputer readable medium produce an article of manufacture includinginstructions which when executed, cause a computer to implement thefunction/act specified in the flowchart and/or block diagram block orblocks. The computer program instructions may also be loaded onto acomputer, other programmable instruction execution apparatus, or otherdevices to cause a series of operational steps to be performed on thecomputer, other programmable apparatuses or other devices to produce acomputer implemented process such that the instructions which execute onthe computer or other programmable apparatus provide processes forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks.

FIG. 16 is a block diagram illustrating a semiconductor devicemanufacturing apparatus (or system) 1000 according to some embodimentsof the present invention.

Referring to FIG. 16, the semiconductor device manufacturing apparatus1000 according to the current embodiment may include a weak featureidentification unit 110, a region classifying unit 130, a shot methoddetermination unit 150, an exposure unit 170, a storage unit 190, and acontrol unit 250.

The weak feature identification unit 110 detects weak features havinghigh possibility of causing pattern failure of patterns to be formed ona target substrate through modelling or a predetermined rule. Themodelling and the predetermined rule are described with reference to,for example, FIGS. 2 and 3. The region classifying unit 130 classifiesthe identified weak features as at least two shot regions according todistances between vertexes in the weak features. For example, a weakfeature may be classified as a first shot region onto which a singleshot is performed and a second shot region onto which at least two shotsare performed. Alternatively, the shot regions may be classifiedaccording to the number of shots. Also, the shot regions may beclassified according to the dosage. The method of classifying shotregions are described with reference to, for example, FIGS. 10A through10E.

The shot method determination unit 150 determines the method of shotsaccording to the classified shot regions. For example, the shot methoddetermination unit 150 may determine dosage data for the classifiedregions and data of the number of shots according to each of the shotregions. More specifically, the shot method determination unit 150 maydetermine to perform a single shot onto the first shot region and toperform at least two shots onto the second shot region. Also, the shotmethod determination unit 150 may determine to perform a shot with aregular dosage onto the first shot region and to performed shots with arelatively large dosage onto the second shot region.

The exposure unit 170 performs exposing to the classified shot regionsby applying different shot methods based on dosage data and a data ofnumber of shots, which are determined by the shot method determinationunit 150. The exposure unit 170 may include a laser source or an e-beamapparatus for performing the exposure process. The exposure unit 170 mayalso include various constituent elements besides the laser source orthe e-beam apparatus. For example, when an exposing is performed byusing a laser source, the exposure unit 170 may include a projectionoptical system, an illumination optical system, a plurality of shutters,and a control device. The exposing unit 170 may include a variableshaped beam (VSB) writing mode exposing device. The VSB writing modeexposing device may expose a designed pattern with a unit rectangularshape or a unit triangular shape as a single shot region. Also, the VSBwriting mode exposing device may realize both the overlap shot methodand the method of shot by controlling a dosage.

The storage unit 190 may store data of modelling or a predetermined rulefor identifying a weak feature or data for classifying regions. Also,the storage unit 190 may store and provide data required in the weakfeature identification unit 110, the region classifying unit 130, theshot method determination unit 150, the exposure unit 170, and thecontrol unit 250, and also may store results provided by the weakfeature identification unit 110, the region classifying unit 130, theshot method determination unit 150, the exposure unit 170, and thecontrol unit 250.

The control unit 250 generally controls the semiconductor devicemanufacturing apparatus 1000. That is, the control unit 250 may controlthe weak feature identification unit 110, the region classifying unit130, the shot method determination unit 150, the exposure unit 170, andthe storage unit 190. In the case of the exposure unit 170, a controlunit for the exposing unit may be additionally connected to the controlunit 250.

A semiconductor device manufacturing apparatus according to someembodiments can identify weak features in patterns to be formed througha weak pattern detection unit, classify the identified weak features asat least two shot regions through a region classifying unit, determinedifferent shot methods for each of the classified shot regions through ashot method determination unit, and perform exposures with the shotmethods determined by an exposure unit. Therefore, the semiconductordevice manufacturing apparatus may reduce pattern failures whilemaintaining a process stability.

While the inventive concept has been particularly shown and describedwith reference to exemplary embodiments thereof, it will be understoodthat various changes in form and details may be made therein withoutdeparting from the spirit and scope of the following claims.

What is claimed:
 1. A semiconductor device manufacturing apparatuscomprising: a weak feature identification unit configured to identifyweak features from among a plurality of features included in aphotolithography pattern to be formed on a mask or a substrate, whereina possibility of failure of the weak features is greater than areference value; a region classification unit configured to classify theweak features to include first and second regions; a shot methoddetermination unit configured to determine respective first and seconddosages for the first and second regions; and an exposure unitconfigured to expose on the first and second regions with the first andsecond dosages.
 2. The apparatus of claim 1 wherein the shot methoddetermination unit is configured to determine the first and seconddosages and the exposure unit is configured to expose the first andsecond regions based on the first and second dosages.
 3. The apparatusof claim 1 wherein the exposure unit comprises a laser light source oran e-beam source.
 4. The apparatus of claim 1 further comprising: astorage unit configured to store data of modeling or a predeterminedrule configured for use by the weak feature identification unit.
 5. Theapparatus of claim 4 wherein the weak feature identification unit isconfigured to identify a feature as the weak feature when a distancebetween a vertex of the feature and another feature of the pattern iswithin a predetermined range and when a number of vertexes included in aunit area of the pattern is greater than a predetermined number.